Key operated lock

ABSTRACT

A lock including a body having a cylindrical bore therethrough in which a plug is rotatably mounted. Apertures in the body slidably receive drivers. The drivers are aligned, in one position of the lock, with tumbler assemblies movably mounted in the plug. The tumbler assemblies extend into a key slot in the plug, and insertion of a key in this slot biases the several tumbler assemblies to a lock-opening position in which the tumbler assemblies contact the drivers along a shear line lying in the interface between the plug and the body. The tumbler assemblies are adjustable in their dimensions by the use of a change key so that they may be altered to permit a new key to be made operative for opening the lock. One part of each tumbler assembly carries a projecting flange which projects through a radial slot in the plug into one of a plurality of L-shaped slots formed in a master key insert assembly. The master key insert assembly is positioned in a slot in the plug which extends substantially parallel to the key slot. The master key insert assembly includes an insert plate having a plurality of the described L-shaped slots formed therein which slidably accommodate L-shaped pins. One leg of each L-shaped pin projects into the key slot in a position for cooperation with the milled surface of a master key, so that when a master key correlated to the particular master key insert assembly in use is placed in the key slot, the L-shaped pins are biased by the milled surface of the master key to a lock-opening position. The second end of each of the L-shaped pins bears against the flange carried by one portion of each tumbler assembly so that displacement of the L-shaped pins by the master key moves the tumbler assemblies to a lock-opening position. The master key insert assembly is slidably disposed in a slot formed in the plug, and is retained in the slot by cooperating retainer pins slidably positioned in the plug and in the master key insert plate. A removal tool passageway is provided in the insert plate in alignment with one end of the retainer pin slidably mounted in the insert plate, so that a removal tool may be used to bias this pin to a position in which the retainer pin in the insert plate meets the retainer pin slidably mounted in the plug along a shear line such that the master key insert assembly may be slidably removed from the plug. After removal of the master key insert assembly in the manner described, a new master key insert may be slidably inserted in the plug so that a new master key must be utilized to open the lock.

[4 1 June 6, 1972 [54] KEY OPERATED LOCK [72] Lewis J. Hill, 4121 NW. 61st Terrace,

Oklahoma City, Okla. 731 12 Jan. 11, 1971 inventor:

Filed:

Appl. No.:

[56] References Cited UNlTED STATES PATENTS 3/ l 940 Fremon ..70/364 A 5/1967 Hill ....70/384 2/ l 970 Schlage... ....70/369 6/1971 Hill ..70/364 A Primary Examiner-Robert L. Wolfe AImmeyDunlap, Laney, Hessin & Dougherty l 5 7 1 ABSTRACT A lock including a body having a cylindrical bore therethrough in which a plug is rotatably mounted. Apertures in the body slidably receive drivers. The drivers are aligned, in one position of the lock, with tumbler assemblies movably mounted in the plug. The tumbler assemblies extend into a key slot in the plug, and insertion of a key in this slot biases the several tumbler assemblies to a lock-opening position in which the tumbler assemblies contact the drivers along a shear line lying in the interface between the plug and the body. The tumbler assemblies are adjustable in their dimensions by the use of a change key so that they may be altered to permit a new key to be made operative for opening the lock.

One part of each tumbler assembly carries a projecting flange which projects through a radial slot in the plug into one of a plurality of L-shaped slots formed in a master key insert as sembly. The master key insert assembly is positioned in a slot in the plug which extends substantially parallel to the key slot. The master key insert assembly includes an insert plate having a plurality of the described L-shaped slots formed therein which slidably accommodate L-shaped pins. One leg of each L-shaped pin projects into the key slot .in a position for cooperation with the milled surface of a master key, so that when a master key correlated to the particular master key insert assembly in use is placed in the key slot, the L-shaped pins are biased by the milled surface of the master key to a lockopening position. The second end of each of the L-shaped pins bears against the flange carried by one portion of each tumbler assembly so that displacement of the L-shaped pins by the master key moves the tumbler assemblies to a lock-opening position.

The master key insert assembly is slidably disposed in a slot formed in the plug, and is retained in the slot by cooperating retainer pins slidably positioned in the plug and in the master key insert plate. A removal tool passageway is provided in the insert plate in alignment with one end of the retainer pin slidably mounted in the insert plate, so that a removal tool may be used to bias this pin to a position in which the retainer pin in the insert plate meets the retainer pin slidably mounted in the plug along a shear line such that the master key insert assembly may be slidably removed from the plug. After removal of the master key insert assembly in the manner described, a new master key insert may be slidably inserted in the plug so that a new master key must be utilized to open the lock.

14 Claims, Drawing Figures KEY OPERATED LOCK BACKGROUND OF THE INVENTION 1. Related Patent Applications This patent application contains subject matterclosely related to the subject matter disclosed in my co-pending U.S. Pat. application Ser. No. 11,668 filed Feb. 16, 1970, now U.S. Pat. No. 3,589,153 issued June 29, 1971 and entitled Key Operated Lock."

2. Field of the Invention This invention relates generally to improved key operated locks. More particularly, but not by way of limitation, this invention relates to an improved key operated lock incorporating mechanism adapted to permit the lock to be easily and rapidly changed for operation by different individual keys, and also to be changed so that a selected master key can be utilized for opening a number of such locks.

BRIEF DESCRIPTION OF THE PRIOR ART In my U.S. Pat. No. 3,320,781 and in my co-pending U.S. Pat. application, Ser. No. 1 1,668, filed Feb. 16, 1970, I depict and describe locks which can be quickly and easily structurally altered so that a difierent key can be used to operate such locks, and the key previously operable for opening the lock will no longer do so. In addition to the individual, regular usage keys adapted to open the individual locks involved, and individually correlated to each individual lock of this type, one of the lock structures shown in my U.S. Pat. No. 3,320,781, contemplates a construction of such locks which are susceptible to being opened by a master key, so that a plurality of such locks, while being openable by individual keys in the hands of certain classes of persons, can also all be opened by one master key in the hands of selected custodians.

It is, of course, desirable to be able to change one or more locks in a business establishment, or even in homes, so that the key normally used for opening the lock is changed, and an old key which has previously been operative to open the lock will no longer work, but only a new key. The locks of the type here under discussion have been characterized in being susceptible to having the tumblers and plungers forming portions of the lock mechanism changed in their operative status relative to each other without the necessity of disassembling the lock, or removing it from the door in which it is located.

In large business establishments such as motels, hotels, and chains of department stores, a great many locks are frequently utilized which are of the general type described. In most cases, it is desirable to provide a master key which will unlock any one of these locks in the event persons in possession of the regular keys for unlocking the locks should leave the door in a locked status, or in the event that it should be desirable to hurriedly open the door which is locked by such locks without seeking out the individual key for the respective lock.

With the provision of one or more master keys which are maintained in the custody of a few selected personnel, the versatility in utilization of this type of lock in a multi lock situation is increased. Situations arise, however, from time to time, in which a custodian of a master key leaves the employ of the organization where the locks are utilized, and, through inadvertence or intent, takes one of the master keys which will unlock any of the locks in use of the type described, and will continue to unlock such locks even though the dimensions of the tumblers in the locks may be changed to accommodate new individual patron keys. The security of the establishment is obviously compromised by the loss of master keys in this manner, and it is therefore desirable to be able to change the locks so that master keys which would previously efiectively unlock or open the locks can no longer be used, and new master keys are required for this purpose. It is further desirable that the ability to change the mechanism of the lock for the purpose of accommodating a new master key be accomplished without the necessity for removing the lock from the door or disassembling the lock.

BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention constitutes an improved key operated lock which includes the change key features described in my U.S. Pat. application, Ser. No. 11,668, but which further incorporates an important improvement in that the lock mechanism can be changed to permit different master keys to be utilized for the purpose of opening the lock regardless of the configuration of any individual patron key which may be operative to open the lock at any time.

Broadly described, the lock of the present invention comprises a body having a cylindrical bore formed therein, and having an elongated plug rotatably mounted in this bore. At one end of the cylindrical bore in the body, an indentation or recess is formed radially in the body for the purpose of receiving a retainer pin slidably carried in the plug. A plurality of drivers are movably positioned in apertures which extend radially in the body and communicate with the bore therethrough. A plurality of adjustable tumbler assemblies are movably positioned in radially extending openings in the plug, and are aligned for contact with the drivers when the plug is rotated to a predetermined position within the body.

The plug has an axially extending change key slot formed therein, and extending parallel to the axis of the cylindrical bore when the plug is mounted in the body, and a main key slot extending over the length thereof and extending parallel to the change key slot. A plurality of axially spaced, circumferentially extending slots extend between the change key slot and the radially extending, tumbler-accommodating openings in the plug and accommodate cam plates movably mounted in the plug for cooperation with a change key inserted in the change key slot. A plurality of axially spaced flange-accommodating slots extend between the tumbler-accommodating openings in the plug and a master key insert assembly slot in the plug to permit flanges carried by each tumbler assembly to extend into a position for cooperation with certain portions of the master key insert assembly.

The improvement provided by the present invention is based structurally upon the provision of the described flanges carried by the tumbler assemblies and extending into a position for cooperation with portions of the master key insert assembly, and in the provision of the master key insert assembly which is slidably mounted in the master key insert slot in the plug, and is detachable from the plug by the use of an insert removal tool as hereinafter described. The remaining portions of the lock, including the construction of the tumblers, the locking pins provided for adjustably interlocking the relatively movable parts of each tumbler, and the cam plates utilized for permitting the tumbler dimensions to be adjusted upon cooperation of the cam plates with a change key, are all of a construction shown and described in detail in my co-pending Pat. application, Ser. No. I 1,668, and such patent application is incorporated herein by reference.

The master key insert assembly which is slidably positioned in the master key insert slot in the plug of the lock comprises a supporting plate which has a plurality of L-shaped slots spaced axially therealong. The supporting plate extends axially in the plug with respect to the axis of the cylindrical bore formed in the body of the lock. The L-shaped slots accommodate L- shaped pins, each of which has one end projecting from the respective L-shaped slot in which it is located into the main key slot formed in the plug. These ends of the L-shaped pins are thus positioned for cooperation with a master key inserted in the main key slot. The other end of each L-shaped pin bears against one of the flanges, to which reference has previously been made, carried by one of the tumbler assemblies slidably mounted in one of the radially extending openings in the plug. The cooperation between the L-shaped pins and the flanges of the tumbler assemblies is such that insertion of a master key in the main key slot effectively biases the several L-shaped pins to a position such that the flanges cooperating with these pins, and secured to the several tumbler assemblies of the lock, are moved to a lock-opening position. Movement of these flanges moves the tumbler assemblies to a position to permit the plug to be freely rotated within the body, and the lock to be opened.

At one end of the supporting plate of the master key insert assembly, this plate carries a retainer pin passageway in which a retainer pin is movably mounted. A removal tool bore is formed in the supporting plate and intersects the retainer pin passageway at a right angle. Aligned with the retainer pin aperture is a second retainer pin passageway formed in the plug, and a second retainer pin is slidably located in this passageway in the plug, and is aligned with and cooperates with the retainer pin disposed inthe retainer pin passageway formed in the supporting plate. The retainer pin passageway in the plug is also positioned in the plug such that when the plug is rotated to a predetermined position, this passageway is aligned with the recess or indentation formed in the body for the accommodation of the retainer pin.

A master key insert removal tool is provided which may be insertedin the removal tool bore, and when so inserted, will bias the retainer pin in the supporting plate to a position such that the retainer pin in the supporting plate contacts the retainer pin in the plug along a shear line lying in the interface between the supporting plate and the plug. Concurrently, the master key insert removal tool is interlocked with the retainer pin in the supporting plate so that, by pulling on the removal tool along a line extending parallel to the axis of the bore through the body, the master key insert assembly may be slidingly withdrawn from the plug in which it is mounted.

After the master key insert assembly has been thus removed, it may be replaced by a different master key insert in which the dimensions of the several L-shaped pins carried thereby are different from those of the master key insert assembly previously in use, and are correlated to the milled surface of a new master key. With the replacement of the master key insert assembly in the manner described, the old master key previously possessing the capability of opening the lock is no longer operative for this purpose, and a new master key correlated to the new master key insert must be utilized.

From the foregoing description of the invention, it will be perceived that it is an object of the invention to provide an improved key operated lock which includes simple and mechanically strong mechanism which is susceptible to selective change in relative dimensions so that regular individual keys usedtherein may be quickly changed, and so that master keys provided for the operation of such locks, regardless of the regular individual keys which are employed for opening the locks, can also be quickly and easily changed without the necessity for disassembling the locks or'removing them from the doors in which they are located.

A further object of the invention is to provide a key operated lock which is characterized in having a long and trouble free operating life, and in which lock the regular key and the master key useful for operating the lock may be quickly rendered inoperative, and the lock accommodated to trouble'free response to selected new individual and master keys.

Another object of the invention is to provide an improved key operated lock in which both the regular key and the master key responsive locking elements within the lock structure can be selectively altered to accommodate new keys of both types quickly and easily.

Additional objects and advantages of the invention will become apparent from the following detailed description of the invention, and from the accompanying drawings which illustrate the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end elevation view of a key operated lock constructed in accordance with the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2.

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1.

FIG. 6 is a sectional view taken along line 6-6 of FIG. 4.

DETAILED DESCRIPTION or A PREFERRED EMBODIMENT OF THE INVENTION Referring initially to FIG. 1 of the drawings, the key operated lock of the invention includes a body 12 which is illustrated as being generally cylindrical in form and is sometimes referred to in the trade as the cylinder." The body 12 has a cylindrical bore 14(see FIG. 3) extending therethrough and a plurality of apertures 16 which extend radially through one wall of the body 12 into the cylindrical bore 14. An elongated plug 18, which is preferably generally cylindrical in configuration, is rotatably mounted in the cylindrical bore 14 in the body 12. On a planar end face of the body 12 which is seen in the end elevation view of FIG. 1 of the drawings, an index mark 20 is provided on the face of the body, and an index mark 22 is provided on the face of the plug I8. The purpose of the indices marks 20 and 22 will be described more fully hereinafter.

As can be seen most clearly in FIGS. 2, 5 and 6, the body 12 1 includes a circumferential flange 24 which extends around one end of the body. The purpose of the flange 24 is to abut the face of a door or other member in which the lock is to be installed. The body 12 has an external thread 26 which is provided to secure the lock in the door or other member where the lock is to be used. An elongated, dove-tailed groove or slot 28 (see FIG. 3) extends from one end of the body 12 to the flange 24 and is provided to accommodate a plate 30 which, when placed in the slot 28, covers the apertures 16 in the body.

A driver 32 is slidingly positioned in each of the apertures 16 in the body 12. Each driver 32 is constantly urged toward the plug 18 by a spring 34 which has one of its ends disposed in a recess or bore in the respective driver 32 and its opposite end abutting the elongated plate 30.

The body 12 has a shallow counterbore 36 in the end thereof which carries the flange 24, and this counterbore intersects the cylindrical bore 14 in the at a shoulder 38. The plug 18 is provided at one of its ends with an annular flange 39 dimensioned to rotatably fit within the counterbore 36 and abut against the shoulder 38 when the plug 18 is inserted in the cylindrical bore 14 in the body 12. At the end of the plug 18 opposite the flange 39, the plug has secured thereto in any suitable manner (such as by screws or the like) a lock cam 46 which serves the dual purposes of preventing the plug 18 from moving toward the forward end of the lock within the body 12, and to actuate a lock bolt (not shown) in a manner well understood in the art.

A main key slot 48 extends longitudinally through the plug 18 and is suitably configured to accept a key for operating the lock. The key used in the main key slot 48 may be an individual patron key for everyday usage, or may be a master key with the function and mode of use of the two keys being hereinafter described in greater detail.

A plurality of apertures 52 extend radially in the plug 18 and have one end in communication with the key slot 48. The apertures 52 open at the outer periphery of the plug 18 and are positioned to register with the apertures 16 in the body 12 when the plug 18 is in the position within the body shown in FIGS. 1 and 2. The apertures 52, in the illustrated embodiment of the invention, are each generally cylindrical in configuration and are each dimensioned to receive a generally cylindrical tumbler assembly 56 (see FIGS. 2 and 3). I

. Each of the tumbler assemblies 56 includes a hollow cylindrical housing 60 which is closed at one end thereof and slidingly disposed within one of the cylindrical apertures 52 in the plug 18. Slidingly disposed within the interior of the cylindrical housing 60 is an extensible member 64 which has an upper portion 65 carrying a plurality of spaced circum-.

ferential flanges 66, and a lower portion 68 which, when installed in the lock 10, extends into the main key slot 48 to a position for contacting a key inserted in the slot as depicted in FIG. 2 and hereinafter described in greater detail. A spring member 70 is provided between the closed end 62 of the hollow cylindrical housing 60 and the upper portion 65 of the extensible member 64 to constantly urge the extensible member away from the closed end of the cylindrical housing and toward the main key slot 48.

A hollow projection 72 extends outwardly from one side of the hollow cylindrical housing 60 and is adapted to receive a portion of a locking pin designated generally by reference numeral 74, The locking pin is of T-shaped configuration and includes a projecting flange portion 76, a barrel 78, and a tip 80 formed on the end of the barrel which is opposite the flange portion 76 (see FIG. 3). The barrel 78 of the locking pin 74 projects through a bore formed in the hollow projection 72 which extends outwardly from one side of the cylindrical housing 60. It will further be noted that the tip 80 of the locking pin projects between the spaced, circumferential ribs 66 of the upper portion 65 of the extensible member 64. The locking pin thus functions to engage the hollow cylindrical housing 60 of the tumbler assembly 56 with the extensible member 64.

Each of the generally cylindrical apertures 52 formed in the plug 18 opens at one of its sides into a substantially semicircular slot 82 cut radially inwardly into the side of the plug 18 and of the general configuration shown in FIG. 3. There is one of the slots 82 cut in the body of the plug 18 in correspondence to each one of the apertures 52, with the series of longitudinally spaced slots 82 in the plug registering with the series of radially extending, longitudinally spaced apertures 52 formed therein. The series of slots 82 cut in one side of the plug 18 are intersected by a longitudinally extending slot 84 cut along a major portion of the length of the plug and extending from the outer surface of the plug in a radially inward direction. At its base, the longitudinally extending slot 84 intersects a relatively small, axially extending change key slot 86 which extends through the plug 18 in a direction parallel to the slot 84 and extends radially inwardly therefrom. This relationship is perhaps best illustrated in FIG. 3 of the drawings where a change key 88 is depicted in position in the change key slot 86, and the lower portion of the longitudinally extending slot 84 is perceptible in full lines and its upper portion in dashed lines.

A cam plate 90 is provided in a cooperating relationship with each of the tumbler assemblies 56. The cam plate 90 has a flat surface 92 which bears against the flange 76 of the locking pin 74 and has a rounded cam surface 94 on the opposite side of the cam plate from the flat surface. One of the cam plates 94 is provided for contact with each of the locking pins 74, and each cam plate is elongated and relatively thin in configuration as can be seen in referring to these elements in FIGS. 2 and 3.

Each of the cam plates 90 has locating pins 96 projecting from the opposite sides thereof. The cam plates 90 are positioned in the several semicircular slots 82 with the locating pins extending into the longitudinal slot 84 in the plug 14 in the manner best illustrated in FIG. 2. The cam surfaces 94 of the several cam plates 90 will, in most positions of the plug 18 within the housing 12, bear against the cylindrical wall of the bore 14 in the housing. In one position to which the plug 18 may be rotated, however, the cam surfaces 94 of the several cam plates 90 are aligned with the apertures 16 in the body 12 which receive the drivers 32. This position of the cam plates is depicted in FIG. 3. It will be noted that when the plug 18 is rotated to the position shown in FIG. 3, the cam plates 90 may be moved radially outwardly, as may the locking pins 74 with which these plates are in contact. As will be subsequently explained, this status of the lock permits the change key 88 to be utilized for biasing the locking pins 74 to a disengaging status so that the extensible members 64 and hollow cylindrical housings 60 may undergo movement relatively to each other.

There is further provided in the cylindrical plug 18, a master key insert assembly slot 100. This elongated slot 100 extends substantially parallel to the main key slot 48 and is of generally L-shaped cross-sectional configuration, with a portion of the insert assembly slot intersecting the main key slot 48 as best illustrated in FIGS. 1, 3 and 4.

Machined radially inwardly in the plug 18 are a plurality of flange accommodating slots 102. The flange accommodating radial slots 102 are axially spaced along the plug 18 and establish open communication between the cylindrical apertures 52 which receive the several tumbler assemblies 56, and the L-shaped master key insert assembly receiving slot 100. To further describe the location of the radial accommodating slots 102, these slots are circumferentially aligned with, and in the same plane as, the tumbler assembly receiving apertures 52 and the circumferential slots 82, previously described. Each of the flange accommodating slots 102 receives a flange 104 which projects from the opposite side of the cylindrical housing 60 from the side thereof from which the hollow projection 72 extends (see FIGS. 3 and 5). Each of the tumbler assemblies 56 carries one of the flanges 104, the number of flanges 104 being in correspondence to the number of flange accommodating slots 102 provided along the length of the plug 18, and these flanges are responsive to the movement of certain portions of a master key insert assembly as more fully hereinafter described.

A master key insert assembly utilized in the lock of the present invention is depicted in the drawings and designated generally be reference numeral 106. The master key insert assembly 106 is slidably positioned in the cylindrical plug 18 in the insert assembly slot so that, under certain conditions hereinafter described, the insert assembly may be made to slide longitudinally within the plug 18. The master key insert assembly 106 includes an insert plate or supporting plate 108 which is generally of L-shaped configuration in conformation to the geometry of the insert assembly receiving slot 100.

The supporting plate 108 has a solid end portion which is disposed adjacent the flanged end portion of the plug 18 when the insert assembly is disposed in the insert assembly slot 100. A small removal tool aperture or bore 110 is formed in this portion of the supporting plate 108 for the purpose of receiving a removal tool as hereinafter described. The removal tool bore 110 extends axially in the supporting plate 108 for a short distance as best depicted in FIG. 6. A radially extending retainer pin passageway 112 extends substantially normal to the removal tool bore 110, as best shown in FIGS. 4 and 6 of the drawings, and slidingly receives a retainer pin 1 14.

It will be noted that one end of the retainer pin 1 14 projects into the removal tool bore 110. The opposite end of the retainer pin 114 bears against a cooperating retainer pin designated generally be reference numeral 1 16. The cooperating retainer pin 116 is slidingly positioned within a radial passageway 118 formed in the cylindrical plug 18 in a position of alignment with the retainer pin passageway 112 in the supporting plate 108. The retainer pin passageway l 18 is partially closed (crimped inwardly) at its end adjacent the supporting plate 108 to form a stop or abutment against which a collar 120 carried on the cooperating retainer pin 116 bears in one position of this pin. The passageway 118 is configured so as to include a relatively large diameter bore portion 118a in which the collar 120 may slidingly reciprocate, and a relatively small diameter counterbore portion 1 18b. A stern portion 122 of the cooperating retainer pin has a portion thereof surrounded by a helical spring 124 and a portion thereof which projects into the relatively small diameter counterbore portion l18b of the passageway 118. The retainer pin passageway 118 formed in the cylindrical plug 18 is positioned so that, when the plug is rotated within the body 12 to a position illustrated in FIG. 4, the retainer pin 116 is aligned with a small recess 126 formed in the internal wall of the body 12 which defines the cylindrical bore 14 extending therethrough. From the description of the construction, configuration and relative location of the retainer pins 114 and 116, it will be perceived that each may move axially within the respective passageways 112 and 118 so that a portion of the small diameter stem portion 122 of the retainer pin 116 will extend into the recess 126 formed in the body 12, and the retainer pin 114 will meet the retainer pin 116 along a line which lies in the same plane as the line ofcontact between the supporting plate 108 of the insert assembly 106 and the cylindrical plug 18.

In the L-shaped supporting plate 108, the master key insert assembly 106 further includes a plurality of L-shaped slots 130 formed in the supporting plate and spaced axially along its length. A guide bar 132 (see FIGS. 3 and 5) cooperates with the supporting plate 108 in retaining in the several L-shaped slots 130 formed in the supporting plate, a plurality of L- shaped pins 134. Each of the L-shaped slots 130 is oversized in relation to the L-shaped pin 134 located therein so that each L-shaped pin may slide axially within its respective L-shaped slot-that is, each L-shaped pin may move in a direction which is coaxial with respect to the relatively longer of the two legs of the pin. One of the ends of each L-shaped pin 134 projects into the main key slot 48, as best illustrated in FIGS. 3 and 4, and the other end of each L-shaped pin is located adjacent one of the flanges 104 carried by each tumbler assembly 56 as hereinbefore described. This relationship is shown in FIGS. 3 and 5. The length of the longest of the two legs of each of the L-shaped pins 134 varies from one of these pins to the next, with the lengths of these legs of the pins being correlated to the milled surface of a master key. Due to this correlation, when a master key is inserted in the main key slot 48, the L-shaped pins 134 are. biased by contact with the milled, key engaging surface of the master key to a position such that all of the ends of the several L-shaped pins which contact the flanges 104 are aligned in a single plane within the cylindrical plug 18. The function of the L-shaped pins 134 will become more apparent when the operation of the lock is subsequently described.

Several types of keys and a removal tool are used in conjunction with thelock structure which has been described. Thus, an individual patron key which is milled to unlock only a specific individual lock of the type under discussion is utilized in the normal utilization and operation of the lock, and this type of key is depicted in position in FIGS. l-4 of the drawings, and is designated by reference numeral 150. A change key 88, utilized for changing the dimensions of the tumbler assemblies 56 of the lock mechanism so that these assemblies are responsive to a new and different individual patron key, is provided for insertion in the change key slot 86 and a change key of this type is illustrated sectionally in FIG. 3. It is also fully illustrated in my co-pending application, Ser. No. I 1,668 filed Feb. 16, 1970.

Additionally, a master key which will function to open a number of locks of the type described, despite their individual respon responsiveness to individually operative patron keys, is also utilized in the main key slot 48, and a master key of the type described is depicted in dashed lines in FIG. 5, and is designated by reference numeral 154. Finally, a removal tool is used with the lock of the present invention for the purpose of removing from the plug 18, the master key insert assembly 106. The removal tool is shownin FIG. 7 and is designated generally by reference numeral 156. The removal tool 156 includes an end portion 158 adapted for insertion inthe removal tool bore 1 10, hereinbefore described, and this end portion is provided with a tapered point and with a recess 160 spaced from the tapered point and adapted to receive one end of the retainer pin 1 14 for a purpose hereinafter described.

OPERATION In some of its functions and in certain modes of operation, the key operated lock of the present invention corresponds closely to the function and modes of operation which characterize the key operated lock described in my co-pending application, Ser. No. 1 1,668, filed Feb. l6, 1970, and entitled Key Operated Lock." For the sake of brevity at some points in the following discussion, it may therefore be deemed expedient to make reference to the cited co-pending application, as well as to my US. Pat. No. 3,320,781, which is also directed to a change key lock generally similar to that which is here under discussion.

The general operation of lock structures which include cooperating drivers and tumbler assemblies of the type described is generally well understood in the art. Locks of this type may be opened at such time as the drivers 32 and the tumbler assemblies 56 cooperate to pemtit the cylindrical plug 18 to be rotated within the body 12. Such rotation of the plug 18 causes the lock cam 46 to be moved against a lock bolt so as to release the door from its surrounding frame and permit the door to be opened. 4

The nomenclature change key lock" which is sometimes applied to locks of the type here under discussion is derived from the capability of the locks to be changed in their internal mechanism so that a key which has previously been efiective for unlocking the lock will no longer perform this function, but rather, a new key must be used for this purpose. In order to accomplish changing of the keys in the manner described, the overall dimensions of the tumbler assemblies 56 are changed so that these tumbler assemblies will no longer cooperate with the milled surface of an individual patron key 150 (previously operative to unlock the lock) in such a way that unlocking can be accomplished, but rather, will be accommodated, by virtue of the changed dimensions, to a new and different key, having a difierent milled surface which is correlated to the particular tumbler dimensions attained after the change is effected.

In order to accomplish the described change in the dimension of the tumbler assemblies 56', the old individual key, which is to be rendered inoperative, is first inserted in thekey slot 48 in the cylindrical plug 18 in the manner depicted in FIGS. 1 and 2 (where the key 150 represents the old individual patron key which it is desired to render inoperative). Upon insertion of this key 150, the overall dimensions of the tumbler assemblies, which are fixed bythe particular interlocking position of the tip 80 of the locking pins 74 with the ribs 66 of the extensible members 65, are such that the closed upper ends 62 of the cylindrical housings 60 are positioned in alignment along a meeting line in contact with the drivers 32. This meeting line coincides with the shear line between the I outer periphery of the cylindrical plug 18 and the wall defining the bore through the body 12. With the drivers 32 and tumbler assemblies 56 in this position relative to each other, the plug 18 can then rotate within the cylindrical bore 14 in the body 12.

For the purpose of opening the'lock, such rotation of the plug 18 is accomplished, and the lock cam 46 then perfonns its function of biasing a lock bolt to an unlatching or unlocking position. Such rotation of the plug 18 also must be effected in order to accomplish the dimensional change in the several tumbler assemblies 56 which is necessary in order to make the lock mechanism responsive to a new individual patron key and render the old key inoperative. For this purpose, the plug 18 is rotated in a clockwise direction, as viewed in FIG. 1, until the indicia mark 22 carried on the plug is aligned with the indicia mark 20 carried on the body 12. It will be perceived that this amounts to a rotation through At this time, the plug 18 is in the position relative to the body 12 shown in FIGS. 3 and 4. When the plug 18 is in this position with the individual key located therein, the cam plates 90 are positioned in alignment with the apertures 16 which carry the drivers 32. Thus, the cam surfaces 94 of the cam plates 90 bear against the inner ends of the drivers 32, and the drivers may thus be biased butwardly in their respective apertures 1,6 against the force resiliently exerted by the springs 34.

With the lock in the status described, a change key 88 of the type shown in my co-pending Pat. application, Ser. No. 1 1,668 is inserted in the change key slot 86 and then comes to occupy the position with respect to the locking pins 74 and cam plates 90 which is illustrated in FIG. '3 of the drawings. The change key 88, when inserted in this manner, effectively biases the several locking pins 74 outwardly with respect to the hollow projections 72. This movement of the locking pins 74 is possible because the cam plates 90 are, at this time, free to move radially outwardly against the drivers 32 which can move outwardly in their respective apertures 16. There is thus effected a disengagement of the tips 80 of the several locking pins 74 from the extensible members 64 forming portions of the tumbler assemblies 56. The extensible members 64 thus become free to move relative to the hollow cylindrical housings 60 of the tumbler assemblies. It will be seen, of course, that the hollow cylindrical housings 60 of the tumbler assemblies 56 are immovable at this time due to the abutment of the closed ends 62 thereof against the wall defining the bore 14 in the body 12.

At this time, the individual patron key 150 may be removed from the main key slot 48. This permits the extensible members 64 forming a portion of each of the tumbler assemblies 56 to be biased by the respective springs 70 to a position where the tapered face of each extensible member adjacent the key slot 48 bears against a shoulder formed within the plug 18. At this point, the movement of the respective extensible member 64 is arrested. With the change key 88 remaining in position, a new individual patron key is then inserted in the key slot 48. This effectively biases the extensible members 64 to new positions which are determined by the geometric configuration of the milled edge of the new key placed in the key slot 48. It also changes the relative positions of the several tips 80 on the locking pins 74 with respect to the ribs 66 formed around the shanks of the extensible members 64.

After the new key has been inserted, the change key 88 is removed from the change key slot 86. This permits the locking pins 74 to respond to the bias of the springs 34 exerted through the drivers 32 and the cam plates 90, and to return to their position of engagement with the extensible members 66 by extension of the tips 80 between adjacent pairs of the spaced ribs 66. It will be perceived that the effect of the actions described is to readjust the overall lengthwise dimension of the several tumbler assemblies 56 so that they are correlated to a new individual key, and this new key, when inserted in the key slot 48, will result in the cylindrical housings 60 of the several tumbler assemblies 56 being biased to the shear line necessary to open the lock as'previously described. The plug 18 may then be rotated in a counterclockwise direction as viewed in FIG. 1 to return it to its original locked status, and the new individual patron key may then be removed. This procedure of changing out the individual keys effective to open the lock is described in detail in my co-pending Pat. application, Ser. No. 1 1,668.

It is often desirable, where a single establishment has in use a number of locks of the type described, to be able to open all of these locks with a single master key. In order to accomplish this, a master key 154 is inserted in the main key slot 48 instead of the individual patron key. Insertion of the master key 154 in this slot results in a milled edge of the master key passing beneath, and biasing to certain predetermined positions, the L-shaped pins 134 carried by the master key insert assembly 106.

The action of the master key 154 in this respect may be perceived in referring to FIGS. 4 and 5. Here it will be noted that the milled edge of the master key 154 has passed beneath and, in effect, wedged upwardly, the several L-shaped pins 134 by contact of this milled edge with the end portion of the L- shaped pins which projects into the main key slot 48. The dimensions of the several L-shaped pins along the longest leg thereof will vary as between the several pins, with such variation in dimension being correlated to the variation in depth of the concave depressions forming the geometric contour of the milled edge of the master key. The correlation is such that, when the proper master key is inserted in the main key slot 48, the upper ends of all of the L-shaped pins 134 (that is, the ends which are in contact with the flanges 104 secured to the tumbler assemblies 56) will be aligned along a single line extending parallel tothe axis of the cylindrical bore 14 through the body 12. Alignment of these ends of the L-shaped pins 134 effectively biases all of the flanges 104 into alignment with each other, and since these flanges are rigidly secured to the hollow cylindrical housings 60 of the tumbler assemblies 56, the result is that these housings are also all biased into alignment. The alignment of the hollow cylindrical housings 60 of the tumbler assemblies 56 is such that the closed ends 62 of these housings are aligned along the shear line between the plug 18 and the body 12. Thus, the condition is satisfied for free rotation of the plug 18 within the body 12, and the lock may be opened as a result of the use of the proper master key.

As has been previously remarked, there may be occasions when one or more of the master keys in use are lost, and the security of the system of locks openable by the master key is therefore compromised. In this event, it is desirable to change the lock mechanisms so that the mechanisms are responsive to a different master key. The lock of the present invention permits this to be accomplished without removal of the bodies or housings of the locks from the doors in which they are located. The process of changing the mechanism to receive a different master key is effected by initially removing from the plug 18, the master key insert assembly 106. This assembly is removed from the insert assembly receiving slot 100 in which it is located by first inserting in the removal tool bore 110, the

v tapered end of the removal tool 156 shown in FIG. 7. As the end portion 158 of the removal tool 156 is pushed into the bore 110, the tapered point of this tool passes under, and wedges upwardly, the retainer pin 1 l4 slidably mounted in the retainer pin aperture 112. As the retainer pin 114 is thus moved upwardly in the slot 114, it forces the cooperating retainer pin 116 carried in the retainer pin passageway 118 outwardly in this passageway against the bias of the spring 124. The radially outer end of the retainer pin 116 at this time extends into the recess 126 in the body 12.

Continued movement of the end portion 158 of the removal tool 156 into the removal tool slot 110 eventually brings the recess or notch 160 formed in the removal tool into alignment with the retainer pin 114. The retainer pin 114 then snaps into the recess 160 and is thus permitted to move to a position such that the retainer pin 114 and the retainer pin 116 meet in the plane containing the abutting surfaces of the supporting plate 108 and plug 18. In this position, neither of the retainer pins 114 or 116 offer obstruction to the sliding movement of the supporting plate 108 in the slot 100. The entire master key insert assembly 106 may thus be pulled outwardly to disengage it from the plug 18. The outward movement of the master key insert assembly 106 is facilitated by the engagement of the retainer pin 1 14 with the recess 160 in the removal tool 156.

Once the master key insert assembly 106 has been pulled out of the plug 118, the removal tool 156 may be disengaged from the insert assembly 106 by rotating the removal tool through C, or sufficiently to disengage the recess 160 from the end of the retainer pin 114. The removal tool may, in this manner, be disengaged or freed from the master key insert assembly 106. A new master key insert assembly 106 which is constructed to respond to a different master key is then positioned in the master key insert assembly slot in the plug 18. To accomplish this, the insert assembly 106 is then pushed into the insert assembly slot 100. A tapered end on the supporting plate 108 allows the insert assembly 106 to wedge the retainer pin 116 outwardly, so that one end thereof projects into the recess 126 formed in the body 12. The inner end of this retainer pin will then come to ride along the upper surface of the L-shaped supporting plate 108 until the insert assembly is fully seated, at which time the retainer pin 116 will be aligned with the retainer pin 114, and the inner end thereof will snap into the retainer pin aperture 112.

It will be understood that the new master key insert assembly 106 which has been positioned within the plug 18 in the manner described contains L-shaped pins 134 which are differently dimensioned than those forming a portion of the master key insert assembly previously in use. The difference in the dimensions of the L-shaped pins 134 on the new master key insert assembly 106, as compared to the L-shaped pins previously in use is due to the necessity to correlate the dimensions of these pins to the different configuration of the new master key which is to be effective for opening the locks. Thus, when the new master key, having a differently configured milled edge, is inserted in the main key slot 48 after changing out the master key insert assembly 106, the L- shaped pins of the new insert assembly will bear against the milled edge of the new master key in such way that the upper ends of the L-shaped pins 134 which contact the flanges 104 will be brought into alignment along a line which is effective to permit the lock to be unlocked.

Although certain preferred embodiments of the invention have been herein described in order to illustrate the principles of the invention, it will be understood that various changes and innovations in structure can be effected without departure from these principles. Changes and innovations of this type are therefore deemed to be circumscribed by the spirit and scope of the invention except as the same may be limited by the appended claims or reasonable equivalents thereof.

What is claimed is:

l. A key operated lock comprising:

a body having a circularly cross-sectioned bore therein;

a plug rotatably mounted in the bore and having a main key slot, a change key slot and a master key insert assembly slot formed therein and extending Substantially parallel to the axis of rotation of the plug in the body;

drivers movably mounted in the body for radial movement relative to the bore in the body, and for movement partially into the bore in the body;

tumbler assemblies movably mounted in the plug for radial movement relative to the bore in the body and movable to a position projecting from the plug, said tumbler assemblies and drivers contacting each other in one position of said plug in relation to said body, said tumbler assemblies each including a plurality of releasably engaged parts movable relative to each other upon disengagement to change the overall dimension of each of the tumbler assemblies;

means for disengaging the relatively movable parts of each tumbler assembly from each other upon insertion of a change key in the change key slot in said plug and rotation of said plug to a predetermined position within said body;

a master key insert assembly slidably positioned in said insert assembly slot, said insert assembly comprising:

a supporting plate; and

a plurality of pins movably mounted on said supporting plate and positioned for cooperation with a master key inserted in said main key slot;

means releasably retaining said master key insert assembly in said insert assembly slot; and

means secured to said tumbler assemblies and extending into contact with said pins for imparting movement to said tumbler assemblies when said pins are moved on said supporting plate by cooperation with a master key.

2; A key operated lock as defined in claim 1 wherein said supporting plate is further characterized in having a plurality of slots therein;

' and wherein said pins are each L-shaped in configuration and have one end projecting into said main key slot, and further have a second end contacting said means secured to said tumbler assemblies.

3. A key operated lock as defined in claim 1 wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pins movably mounted in said plug and said master key insert assembly.

4. A key operated lock as defined in claim 1 wherein said retaining means comprises a retainer pin movably mounted in said plug and engageable in one position with said master key insert assembly.

5. A key operated lock as defined in claim 1 wherein said means secured to said tumbler assemblies comprises a flange secured to, and projecting from, one of the relatively movable parts of each of said tumbler assemblies, said one relatively movable part contacting one of said drivers in said one position of the plug in relation to said body.

6. A key operated lock as defined in claim 1 wherein each of said tumbler assemblies comprises: 5 a hollow housing positioned for contacting one of said drivers when said plug is in said one position; an extensible member movably mounted in said hollow housing for adjusting the overall length of the tumbler assembly, and having a portion projecting into the main key slot for cooperation with a key inserted therein; and

a locking pinreleasably engaging said extensible member with said cap to prevent relative movement therebetween and to selectively fix the length of the tumbler assembly, a

portion of said locking pin projecting into said change key slot.

7. A key operated look as defined in claim 6 wherein said means for disengaging the relatively movable parts of each tumbler assembly from each other comprises a cam plate contacting the locking pin of each tumbler assembly and movably mounted in a slot in said plug, each of said cam plates having a cam surface projecting into contact with the wall of the bore in said body, and each of said cam plates having said cam surface positioned for contacting one of said drivers to permit radial displacement of said locking pins and cam plates upon isertion of said change key and rotation of said plug.

8. A key operated lock as defined in claim 1 wherein said supporting plate is further characterized in having a removal tool bore extending thereinto, and a retainer pin aperture extending thereinto and intersecting said removal tool bore, said retainer pin aperture having an opening adjacent said plug;

and wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises:

a first retainer pin movably positioned in said retainer pin aperture and projecting into said removal tool bore; and

a second retainer pin movably positioned in said plug and positioned for movement of a portion thereof into and out of said retainer pin aperture for cooperation with said first retainer pin.

9. A key operated lock as defined in claim 2 wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pin movably mounted in said plug and said master key insert assembly.

10. A key operated lock as defined in claim 2 wherein said means secured to said tumbler assemblies comprises a flange secured to one of the relatively movable parts of each one of said tumbler assemblies and projecting therefrom into contact with one of said L-shaped pins, said one relatively movable part contacting one of said drivers in said one position of the plug in relation to said body.

11. A key operated lock as defined in claim 10 wherein said 55 means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pins movably-mounted in said plug and said master key insert assembly.

12. A key operated lock as defined in claim 10 wherein said supporting plate is further characterized in having a removal tool bore extending thereinto and a retainer pin aperture extending thereinto and intersecting said removal tool bore, said retainer pin aperture having an opening adjacent said plug, one of said retainer pins being slidably mounted in said retainer pin aperture and having a portion projecting into said removal tool bore.

13. A key operated lock comprising:

a cylindrical body having a cylindrical bore therethrough;

a cylindrical plug rotatably mounted in said body and having formed therein a main key slot and a slot for receiving a master key insert assembly;

drivers movably mounted in said body for radial movement in relation to said cylindrical bore;

tumbler assemblies movably mounted in the plug for'radial movement relative to said cylindrical bore, said tumbler assemblies and drivers contacting each other in one posiinsertable in said main key slot, said means including portion of said plug in relation to said body; lions projecting into said main key slot for cooperation master key insert assembly slidably positioned in said with the milled edge of a master key. second-mentioned lot in aid lug, and in luding means 14. A key operated lock as defined in claim 13 wherein each mo bl i hi id l d contacting id tumbler of said tumbler assemblies is adjustable in its dimensions to semblies for biasing the tumbler assemblies to a lock respond difiFrem y insertefj into Said main y 5101 in opening position upon movement of said means to a Contact tumbler assembhespreselected position correlated to a specific master key 

1. A key operated lock comprising: a body having a circularly cross-sectioned bore therein; a plug rotatably mounted in the bore and having a main key slot, a change key slot and a master key insert assembly slot formed therein and extending substantially parallel to the axis of rotation of the plug in the body; drivers movably mounted in the body for radial movement relative to the bore in the body, and for movement partially into the bore in the body; tumbler assemblies movably mounted in the plug for radial movement relative to the bore in the body and movable to a position projecting from the plug, said tumbler assemblies and drivers contacting each other in one position of said plug in relation to said body, said tumbler assemblies each including a plurality of releasably engaged parts movable relative to each other upon disengagement to change the overall dimension of each of the tumbler assemblies; means for disengaging the relatively movable parts of each tumbler assembly from each other upon insertion of a change key in the change key slot in said plug and rotation of said plug to a predetermined position within said body; a master key insert assembly slidably positioned in said insert assembly slot, said insert assembly comprising: a supporting plate; and a plurality of pins movably mounted on said supporting plate and positioned for cooperation with a master key inserted in said main key slot; means releasably retaining said master key insert assembly in said insert assembly slot; and means secured to said tumbler assemblies and extending into contact with said pins for imparting movement to said tumbler assemblies when said pins are moved on said supporting plate by cooperation with a master key.
 2. A key operated lock as defined in claim 1 wherein said supporting plate is further characterized in having a plurality of slots therein; and wherein said pins are each L-shaped in configuration and have one end projecting into said main key slot, and further have a second end contacting said means secured to said tumbler assemblies.
 3. A key operated lock as defined in claim 1 wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pins movably mounted in said plug and said master key insert assembly.
 4. A key operated lock as defined in claim 1 wherein said retaining means comprises a retainer pin movably mounted in said plug and engageable in one position with said master key insert assembly.
 5. A key operated lock as defined in claim 1 wherein said means secured to said tumbler assemblies comprises a flange secured to, and projecting from, one of the relatively movable parts of each of said tumbler assemblies, said one relatively movable part contacting one of said drivers in said one position of the plug in relation to said body.
 6. A key operated lock as defined in claim 1 wherein each of said tumbler assemblies comprises: a hollow housing positioned for contacting one of said drivers when said plug is in said one position; an extensible member movably mounted in said hollow housing for adjusting the overall length of the tumbler assembly, and having a portion projecting into the main key slot for cooperation with a key inserted therein; and a locking pin releasably engaging said extensible member with said cap to prevent relative movement therebetween and to selectively fix the length of the tumbler assembly, a portion of said locking pin projecting into said change key slot.
 7. A key operated lock as defined in claim 6 wherein said means for disengaging the relatively movable parts of each tumbler assembly from each other comprises a cam plate contacting the locking pin of each tumbler assembly and movably mounted in a slot in said plug, each of said cam plates having a cam surface projecting into contact with the wall of the bore in said body, and each of said cam plates having said cam surface positioned for contacting one of said drivers to permit radial displacement of said locking pins and cam plates upon isertion of said change key and rotation of said plug.
 8. A key operated lock as defined in claim 1 wherein said supporting plate is further characterized in having a removal tool bore extending thereinto, and a retainer pin aperture extending thereinto and intersecting said removal tool bore, said retainer pin aperture having an opening adjacent said plug; and wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises: a first retainer pin movably positioned in said retainer pin aperture and projecting into said removal tool bore; and a second retainer pin movably positioned in said plug and positioned for movement of a portion thereof into and out of sAid retainer pin aperture for cooperation with said first retainer pin.
 9. A key operated lock as defined in claim 2 wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pin movably mounted in said plug and said master key insert assembly.
 10. A key operated lock as defined in claim 2 wherein said means secured to said tumbler assemblies comprises a flange secured to one of the relatively movable parts of each one of said tumbler assemblies and projecting therefrom into contact with one of said L-shaped pins, said one relatively movable part contacting one of said drivers in said one position of the plug in relation to said body.
 11. A key operated lock as defined in claim 10 wherein said means releasably retaining said master key insert assembly in said insert assembly slot comprises cooperating retainer pins movably mounted in said plug and said master key insert assembly.
 12. A key operated lock as defined in claim 10 wherein said supporting plate is further characterized in having a removal tool bore extending thereinto and a retainer pin aperture extending thereinto and intersecting said removal tool bore, said retainer pin aperture having an opening adjacent said plug, one of said retainer pins being slidably mounted in said retainer pin aperture and having a portion projecting into said removal tool bore.
 13. A key operated lock comprising: a cylindrical body having a cylindrical bore therethrough; a cylindrical plug rotatably mounted in said body and having formed therein a main key slot and a slot for receiving a master key insert assembly; drivers movably mounted in said body for radial movement in relation to said cylindrical bore; tumbler assemblies movably mounted in the plug for radial movement relative to said cylindrical bore, said tumbler assemblies and drivers contacting each other in one position of said plug in relation to said body; a master key insert assembly slidably positioned in said second-mentioned slot in said plug, and including means movable within said plug and contacting said tumbler assemblies for biasing the tumbler assemblies to a lock opening position upon movement of said means to a preselected position correlated to a specific master key insertable in said main key slot, said means including portions projecting into said main key slot for cooperation with the milled edge of a master key.
 14. A key operated lock as defined in claim 13 wherein each of said tumbler assemblies is adjustable in its dimensions to respond to different keys inserted into said main key slot in contact with said tumbler assemblies. 